clang-format: fix fallback style set to "none" not always formatting

This fixes clang-format not formatting if fallback-style is explicitly set to
"none", and either a config file is found or YAML is passed in without a
"BasedOnStyle". With this change, passing "none" in these cases will have no
affect, and LLVM style will be used as the base style.

Differential Revision: https://reviews.llvm.org/D28844

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@292562 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 45 insertions, 7 deletions

diff --git a/lib/Format/Format.cpp b/lib/Format/Format.cpp
index e793d003ff..82647b6b2e 100644
--- a/lib/Format/Format.cpp
+++ b/lib/Format/Format.cpp
@@ -1888,8 +1888,8 @@ static FormatStyle::LanguageKind getLanguageByFileName(StringRef FileName) {
 }
 
 llvm::Expected<FormatStyle> getStyle(StringRef StyleName, StringRef FileName,
-                                     StringRef FallbackStyle, StringRef Code,
-                                     vfs::FileSystem *FS) {
+                                     StringRef FallbackStyleName,
+                                     StringRef Code, vfs::FileSystem *FS) {
   if (!FS) {
     FS = vfs::getRealFileSystem().get();
   }
@@ -1903,9 +1903,9 @@ llvm::Expected<FormatStyle> getStyle(StringRef StyleName, StringRef FileName,
       (Code.contains("\n- (") || Code.contains("\n+ (")))
     Style.Language = FormatStyle::LK_ObjC;
 
-  // FIXME: If FallbackStyle is explicitly "none", format is disabled.
-  if (!getPredefinedStyle(FallbackStyle, Style.Language, &Style))
-    return make_string_error("Invalid fallback style \"" + FallbackStyle.str());
+  FormatStyle FallbackStyle = getNoStyle();
+  if (!getPredefinedStyle(FallbackStyleName, Style.Language, &FallbackStyle))
+    return make_string_error("Invalid fallback style \"" + FallbackStyleName);
 
   if (StyleName.startswith("{")) {
     // Parse YAML/JSON style from the command line.
@@ -1977,7 +1977,7 @@ llvm::Expected<FormatStyle> getStyle(StringRef StyleName, StringRef FileName,
     return make_string_error("Configuration file(s) do(es) not support " +
                              getLanguageName(Style.Language) + ": " +
                              UnsuitableConfigFiles);
-  return Style;
+  return FallbackStyle;
 }
 
 } // namespace format
diff --git a/test/Format/style-on-command-line.cpp b/test/Format/style-on-command-line.cpp
index 0d2d69206d..441797f206 100644
--- a/test/Format/style-on-command-line.cpp
+++ b/test/Format/style-on-command-line.cpp
@@ -11,6 +11,21 @@
 // RUN: clang-format -style=file -assume-filename=%T/foo.cpp < %s | FileCheck -strict-whitespace -check-prefix=CHECK7 %s
 // RUN: clang-format -style="{BasedOnStyle: LLVM, PointerBindsToType: true}" %s | FileCheck -strict-whitespace -check-prefix=CHECK8 %s
 // RUN: clang-format -style="{BasedOnStyle: WebKit, PointerBindsToType: false}" %s | FileCheck -strict-whitespace -check-prefix=CHECK9 %s
+
+// Fallback style tests
+// RUN: rm %T/_clang-format
+// Test no config file found, WebKit fallback style is applied
+// RUN: clang-format -style=file -fallback-style=WebKit -assume-filename=%T/foo.cpp < %s 2>&1 | FileCheck -strict-whitespace -check-prefix=CHECK10 %s
+// Test no config file and no fallback style, LLVM style is applied
+// RUN: clang-format -style=file -assume-filename=%T/foo.cpp < %s 2>&1 | FileCheck -strict-whitespace -check-prefix=CHECK11 %s
+// Test no config file and fallback style "none", no formatting is applied
+// RUN: clang-format -style=file -fallback-style=none -assume-filename=%T/foo.cpp < %s 2>&1 | FileCheck -strict-whitespace -check-prefix=CHECK12 %s
+// Test config file with no based style, and fallback style "none", formatting is applied
+// RUN: printf "IndentWidth: 6\n" > %T/_clang-format
+// RUN: clang-format -style=file -fallback-style=none -assume-filename=%T/foo.cpp < %s 2>&1 | FileCheck -strict-whitespace -check-prefix=CHECK13 %s
+// Test yaml with no based style, and fallback style "none", LLVM formatting applied
+// RUN: clang-format -style="{IndentWidth: 7}" -fallback-style=none %s | FileCheck -strict-whitespace -check-prefix=CHECK14 %s
+
 void f() {
 // CHECK1: {{^        int\* i;$}}
 // CHECK2: {{^       int \*i;$}}
@@ -22,6 +37,11 @@ void f() {
 // CHECK7: {{^      int\* i;$}}
 // CHECK8: {{^  int\* i;$}}
 // CHECK9: {{^    int \*i;$}}
+// CHECK10: {{^    int\* i;$}}
+// CHECK11: {{^  int \*i;$}}
+// CHECK12: {{^int\*i;$}}
+// CHECK13: {{^      int \*i;$}}
+// CHECK14: {{^       int \*i;$}}
 int*i;
 int j;
 }
diff --git a/unittests/Format/FormatTest.cpp b/unittests/Format/FormatTest.cpp
index 38095402f0..a7c2f7c9df 100644
--- a/unittests/Format/FormatTest.cpp
+++ b/unittests/Format/FormatTest.cpp
@@ -10978,13 +10978,31 @@ TEST(FormatStyle, GetStyleOfFile) {
   ASSERT_TRUE((bool)Style1);
   ASSERT_EQ(*Style1, getLLVMStyle());
 
-  // Test 2: fallback to default.
+  // Test 2.1: fallback to default.
   ASSERT_TRUE(
       FS.addFile("/b/test.cpp", 0, llvm::MemoryBuffer::getMemBuffer("int i;")));
   auto Style2 = getStyle("file", "/b/test.cpp", "Mozilla", "", &FS);
   ASSERT_TRUE((bool)Style2);
   ASSERT_EQ(*Style2, getMozillaStyle());
 
+  // Test 2.2: no format on 'none' fallback style.
+  Style2 = getStyle("file", "/b/test.cpp", "none", "", &FS);
+  ASSERT_TRUE((bool)Style2);
+  ASSERT_EQ(*Style2, getNoStyle());
+
+  // Test 2.3: format if config is found with no based style while fallback is
+  // 'none'.
+  ASSERT_TRUE(FS.addFile("/b/.clang-format", 0,
+                         llvm::MemoryBuffer::getMemBuffer("IndentWidth: 2")));
+  Style2 = getStyle("file", "/b/test.cpp", "none", "", &FS);
+  ASSERT_TRUE((bool)Style2);
+  ASSERT_EQ(*Style2, getLLVMStyle());
+
+  // Test 2.4: format if yaml with no based style, while fallback is 'none'.
+  Style2 = getStyle("{}", "a.h", "none", "", &FS);
+  ASSERT_TRUE((bool)Style2);
+  ASSERT_EQ(*Style2, getLLVMStyle());
+
   // Test 3: format file in parent directory.
   ASSERT_TRUE(
       FS.addFile("/c/.clang-format", 0,